package com.fary.security.web.util.matcher;

import javax.servlet.http.HttpServletRequest;
import java.util.Collections;
import java.util.Map;

public interface RequestMatcher {

    /**
     * Decides whether the rule implemented by the strategy matches the supplied request.
     *
     * @param request the request to check for a match
     * @return true if the request matches, false otherwise
     */
    boolean matches(HttpServletRequest request);

    /**
     * Returns a MatchResult for this RequestMatcher
     * The default implementation returns  {@link Collections#emptyMap()}
     * when {@link MatchResult#getVariables()} is invoked.
     *
     * @return the MatchResult from comparing this RequestMatcher against the HttpServletRequest
     * @since 5.2
     */
    default MatchResult matcher(HttpServletRequest request) {
        boolean match = matches(request);
        return new MatchResult(match, Collections.emptyMap());
    }

    /**
     * The result of matching against an HttpServletRequest
     * Contains the status, true or false, of the match and
     * if present, any variables extracted from the match
     *
     * @since 5.2
     */
    class MatchResult {
        private final boolean match;
        private final Map<String, String> variables;

        MatchResult(boolean match, Map<String, String> variables) {
            this.match = match;
            this.variables = variables;
        }

        /**
         * @return true if the comparison against the HttpServletRequest produced a successful match
         */
        public boolean isMatch() {
            return this.match;
        }

        /**
         * Returns the extracted variable values where the key is the variable name and the value is the variable value
         *
         * @return a map containing key-value pairs representing extracted variable names and variable values
         */
        public Map<String, String> getVariables() {
            return this.variables;
        }

        /**
         * Creates an instance of {@link MatchResult} that is a match with no variables
         *
         * @return
         */
        public static MatchResult match() {
            return new MatchResult(true, Collections.emptyMap());
        }

        /**
         * Creates an instance of {@link MatchResult} that is a match with the specified variables
         *
         * @param variables
         * @return
         */
        public static MatchResult match(Map<String, String> variables) {
            return new MatchResult(true, variables);
        }

        /**
         * Creates an instance of {@link MatchResult} that is not a match.
         *
         * @return
         */
        public static MatchResult notMatch() {
            return new MatchResult(false, Collections.emptyMap());
        }
    }

}